Packaging containers comprising a first portion essentially being formed of a first material and a second portion essentially being formed of a second material have been known for a long time. One example of such a packaging container is shown in EP-A1-108166. Another example of such a packaging container is disclosed in WO 02/070365 A1. The latter one is a commercially available packaging container marketed by Tetra Pak under the trademark Tetra Top.
The packaging container is manufactured in accordance with the following steps:
a) a roll of a packaging laminate is cut into sheets,
b) the sheets are formed into sleeves by sealing two edges to each other,
c) the sleeves are slid onto a mandrel on a mandrel wheel,
d) a top made of a plastic material is injection moulded onto one end of the sleeve,
e) the container is ejected (standing on its top) from the moulding station to a filling station,
f) the container is filled with a product,
g) the bottom is formed by squeezing the open end and sealing the edge into a transversal seal, and
i) the bottom is finally formed by folding flaps and sealing the flaps to the bottom surface of the bottom.
As described in WO 02/070365 A1, the container thus formed is usually provided with a closed top, being adapted to be opened by removal of a membrane covering the pouring opening. In order to facilitate the opening of the container, the transition between the membrane and the surrounding portions of the top is formed as a weakening line, i.e. a portion having a smaller wall thickness than the surrounding portions.
One advantage with making the packaging container of different materials or material combinations in different portions of the container is that the different portions can be adapted to any desired property being important for respective portion of the package. It is for instance common that a neck on a packaging container has a well-defined shape in order to be able to correctly receive a screw cap or some other kind of opening device and in co-operation with the cap form a tight joint. Preferably, this is achieved using some kind of plastic material for the neck. Furthermore, it is also common that the packaging container is required to have some barrier properties, such as light, taste or oxygen barrier. A plastic material with these properties is more costly than a plastic material without these properties. In such a case is it advantageous to use fibre based packaging laminate with barrier properties. This packaging laminate is a typical example of a portion of the container made of a material combination, the laminate typically comprises a paper or fibre-based layer and one or more plastic layers. In many cases the laminate also comprises an aluminium layer.
There are a number of different reasons to use such multimaterial packages where different portions of the packages are formed of different materials or material combinations. It can e.g. facilitate process, manufacture and transport of different materials. Moreover, the overall appearance of the packaging container is most often more attractive if a packaging laminate forming the package is directly provided with the desired print than if a plastic container is provided with a separate label. Furthermore, fibre based packaging laminates can be transported as rolls, or in crates as flat folded blanks, compared to plastic containers being transported as ready made or as preforms which requires a significantly greater transported volume in comparison to the filled volume in the finished containers.
In some cases there is, however, some drawbacks with containers made of separate materials. When the container has been used and is returned for disposal or some other kind of waste management, this subsequent handling may require that the portions formed of different materials or material combinations are separated from each other. It is for instance common that the waste is sorted into the fractions plastic, paper, metal and glass, i.e. a glass jaw and its metallic lid are to be separated from each other in connection with the waste management. Since this jaw and lid are separate members it is simple and obvious for a consumer that the members made of different materials are to be sorted into different fractions. When the packaging container body itself is made of different materials it becomes trickier. If the separation of the different materials cannot be made in a satisfactory manner, the reuse or recycling cannot be realized and the waste must be burned or deposited. In many cases the waste is nevertheless burned, but also in such a case it might be desirable with a preceding separation since the burning of the waste can be controlled by selectively adding different amounts of the different material fractions over time.
Lately, environmental demands from consumers and authorities have put more pressure on companies producing packaging containers to make a packaging container with the above-mentioned benefits and still being disposable in accordance with waste management systems.